Production of H2S For Efficient Metal Removal From Effluents

Abstract

Method and apparatus pertaining to the production of hydrogen sulfide using sodium salts recycle. Sodium sulfate is reacted with a carbon containing stream to produce sodium sulfide and carbon dioxide. The sodium sulfide is blended with elemental sulfur and water. The blend is subjected to elevated temperatures and pressures to result in the production of hydrogen sulfide and sodium sulfate. A mixing apparatus, such as a bubble column reactor, has been found to be especially useful. The hydrogen sulfide can be used for removing metal from effluents.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Provisional Application No. 63 / 081,585 filed on Sep. 22, 2020, and to provisional Application No. 63 / 014,947 filed on Apr. 24, 2020, the content of both of which are hereby incorporated by reference.BACKGROUND OF THE DISCLOSURE[0002]Hydrogen sulfide is a chemical compound with the formula H2S. At room temperature, it is a colorless, flammable and extremely dangerous gas with the characteristic foul odor of rotten eggs. Chemically, hydrogen sulfide acts as a reducing agent, and reacts with metal ions to form metal sulfides, which may be considered the salts of hydrogen sulfide. In addition, the naturally occurring mineral form of several metals are sulfides (e.g., galena, or lead(II) sulfide and sphalerite, or zinc sulfide).[0003]In regards to health, hydrogen sulfide is both an irritant and a chemical asphyxiant which affects oxygen utilization and the central nervous system. At lower concentrations (2-...

AI Technical Summary

Benefits of technology

The patent describes an innovative and efficient way to produce hydrogen sulfide on-site. This method is safe and cost-effective, and can be used to precipitate metals from solution. The main benefit is that hydrogen sulfide can be produced right where it is needed, eliminating the need for transportation and reducing costs and danger.

Problems solved by technology

At room temperature, it is a colorless, flammable and extremely dangerous gas with the characteristic foul odor of rotten eggs.

At lower concentrations (2-5 ppm), this can cause nausea, tearing of the eyes, headaches and / or loss of sleep.

Higher concentrations (5-100 ppm) can cause more severe eye and respiratory irritation.

At higher concentrations, (100+ ppm) it can cause shock, convulsions, inability to breathe, extremely rapid unconsciousness, coma and death.

In addition, all valuable metals are lost in the sludge.

However obtained, hydrogen sulfide can be very costly to produce because of the dangers involved in production, and because of the hazards it poses to human health.

NaHS used by major mining companies at its mines in Mexico for example generally are imported from the USA by rail, which has the disadvantage of being very expensive, difficult to manage as well as remoteness.

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